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onsemi SA120A
- Part No.:
- SA120A
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA120A.pdf
- Description:
- TVS DIODE 120VWM 193VC DO15
- Quantity:
- Payment:
- Shipping:
Inventory:6,365
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Product details
Overview
SA120A from Fairchild Semiconductor is a unidirectional 500 W transient voltage suppressor (TVS) diode designed for primary-level overvoltage protection in DC power lines and signal interfaces. It features a 120 V reverse stand-off voltage (VRWM), 133–147 V breakdown voltage (VBR) at 1.0 mA, 193 V clamping voltage at peak pulse current, and operates up to +175 °C junction temperature. It is commonly deployed in industrial power supplies and telecom line cards.
For engineers reviewing the SA120A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 µs surge, low leakage (<1 µA at 120 V), fast response time (<1.0 ps), DO-15 package compatibility, and thermal derating behavior above 75 °C ambient.
Technical Context
The SA120A employs a glass-passivated silicon junction optimized for high-energy transient suppression on 10/1000 µs waveforms. Its unidirectional architecture provides asymmetric conduction-low forward voltage drop during normal operation and rapid avalanche breakdown during overvoltage events.
It delivers 500 W peak pulse power with 193 V clamping at rated IPPM of 2.7 A, exhibits <1.0 µA reverse leakage at VRWM, and maintains stable breakdown across temperature due to its junction design and JEDEC-compliant thermal construction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power (10/1000 µs) | 500 W - sustains single high-energy surges without failure in lightning or ESD-prone environments |
| Reverse Stand-off Voltage (VRWM) | 120 V - maximum continuous DC or RMS voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 133–147 V at 1.0 mA - defines precise avalanche initiation threshold for predictable clamping onset |
| Clamping Voltage (VC @ IPPM) | 193 V at 2.7 A - limits protected circuit voltage during surge, enabling downstream IC survival |
| Reverse Leakage (IR @ VRWM) | <1.0 µA - negligible standby power loss and minimal impact on high-impedance sensing nodes |
| Junction Temperature Range | −65 to +175 °C - supports operation in harsh industrial and outdoor enclosures |
Pinout & Package
SA120A is housed in a DO-15 axial-leaded package with cathode indicated by a color band. The device has two terminals: anode and cathode. Lead length is specified at 0.375 inches for thermal rating compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction | Connected to ground or low-side return path in unidirectional TVS configurations |
| Cathode | Current exit terminal; marked with color band | Connected to protected line-avalanche occurs when cathode-to-anode voltage exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enhances long-term reliability and moisture resistance in humid or contaminated environments |
| Fast response time | <1.0 ps rise time enables suppression before sensitive downstream components experience overstress |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients, improving clamping accuracy |
| Excellent clamping capability | 193 V clamping at 2.7 A ensures protected circuits remain within safe operating area during IEC 61000-4-5 surges |
Applications
| Industrial Power Input Protection | Telecom Line Interface |
|---|---|
Use Scenario: 24–48 V DC input stage of programmable logic controllers exposed to load dump and inductive switching transients. IC Role / Device Role: Primary overvoltage clamp placed upstream of DC-DC converters and microcontrollers. Use Value: Limits surge-induced voltage to ≤193 V, preventing damage to 200 V-rated input capacitors and gate drivers. |
Use Scenario: T1/E1 interface card receiving signals from outside plant wiring subject to lightning-induced surges. IC Role / Device Role: Unidirectional TVS on tip/ring lines referenced to system ground. Use Value: Clamps common-mode surges while maintaining <1 µA leakage to preserve signal integrity and bias stability. |
| Automotive Body Control Module | AC-DC Adapter Input Stage |
Use Scenario: 12 V supply rail in BCMs subjected to ISO 7637-2 Pulse 1 and Pulse 2b transients. IC Role / Device Role: Secondary protection device after fuse and upstream of LDO regulators. Use Value: Withstands 500 W pulses without degradation, supporting AEC-Q101-referenced robustness requirements. |
Use Scenario: Input rectifier stage of universal-input (90–264 VAC) offline SMPS. IC Role / Device Role: MOV backup or primary surge clamp on bulk capacitor charging path. Use Value: Provides precise 120 V standoff and 193 V clamping-tighter tolerance than typical MOVs-reducing stress on bridge rectifier and X-capacitor. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ120A | DO-214AA package; 1.0 mm thinner profile; 193 V clamping same, but 1.0 A higher IPPM (3.7 A) | Better suited for PCB space-constrained designs; requires re-layout due to SMD footprint | Select SMBJ120A when surface-mount assembly and higher surge margin are prioritized over through-hole serviceability. |
| P6KE120A | Same DO-15 package; lower peak power (600 W vs. SA120A's 500 W); 193 V clamping; 3.1 A IPPM | Higher surge current capacity but wider VBR tolerance (133–154 V vs. SA120A's 133–147 V) | Choose P6KE120A where legacy stock or broader breakdown tolerance is acceptable, but verify clamping consistency in critical timing circuits. |
Compared with SMBJ120A and P6KE120A, the SA120A offers tighter VBR range and proven thermal stability in leaded industrial assemblies, making it preferred for high-reliability through-hole deployments where mechanical robustness and long-term leakage control are essential.
Availability
SA120A is available at Aetrix Electronics and suitable for industrial power input protection, telecom line interface, automotive body control modules, and AC-DC adapter input stages requiring stable component supply and consistent surge performance across production batches.
Supply support for SA120A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete solutions before its acquisition by ON Semiconductor in 2016. Its TVS portfolio emphasized ruggedness, precision clamping, and wide temperature operation.
The SAxxxA series was engineered specifically for high-energy transient suppression in industrial and telecom infrastructure, balancing tight VBR tolerance, low leakage, and repeatable 500 W surge handling in axial-leaded form factors.
FAQ
What is the clamping voltage of the SA120A under a 10/1000 µs surge?
The SA120A clamps to 193 V when subjected to its rated peak pulse current of 2.7 A on a 10/1000 µs waveform. This value is measured per industry-standard test conditions and ensures predictable overvoltage limiting for downstream components. The SA120A maintains this clamping performance across its full operating temperature range, making it suitable for use in thermally demanding environments where consistent protection is required.
Is the SA120A unidirectional or bidirectional?
The SA120A is a unidirectional transient voltage suppressor, indicated by the absence of the "C" suffix (which denotes bidirectional variants like SA120CA). It conducts only in reverse avalanche mode and must be installed with correct polarity-cathode toward the protected line. The SA120A does not conduct in forward bias beyond typical diode drop, distinguishing it from bidirectional types that protect both polarities.
What is the maximum operating junction temperature for the SA120A?
The SA120A has a maximum operating junction temperature of +175 °C, as specified in its Absolute Maximum Ratings table. This rating allows reliable operation in high-temperature industrial enclosures and near heat-generating components. Derating curves confirm usable power dissipation down to zero watts at 175 °C ambient, assuming proper lead length (0.375") and PCB copper area for thermal conduction.
Does the SA120A meet any industry surge immunity standards?
The SA120A is designed to support compliance with IEC 61000-4-5 (surge immunity) and ISO 7637-2 (automotive transients) when applied per recommended layout and system-level filtering. Its 500 W peak pulse rating on the 10/1000 µs waveform directly maps to Level 3 and Level 4 surge test profiles. System validation is required, but the SA120A provides the foundational clamping performance needed to pass these standards.
How does the SA120A compare to the SA120CA variant?
The SA120CA is the bidirectional version of the same family, offering symmetrical clamping in both directions with identical VRWM (120 V), VBR (133–147 V), and VC (193 V) ratings. Unlike the SA120A, the SA120CA has no cathode marking and is used where AC-coupled or polarity-agnostic protection is needed. The SA120A remains preferred for DC rails where unidirectional blocking and minimal forward conduction are required.
SA120A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-204AC, DO-15, Axial
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 120V
- Voltage - Breakdown (Min):
- 133V
- Voltage - Clamping (Max) @ Ipp:
- 193V
- Current - Peak Pulse (10/1000µs):
- 2.7A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-15
SA120A FAQ
1.How can I place an order for SA120A through Aetrix?
Please submit a Request for Quotation (RFQ) for SA120A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SA120A reliable?
The price and inventory of SA120A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA120A is usually 5 days.
3.What payment methods are accepted for SA120A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA120A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA120A?
SA120A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA120A order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SA120A?
For technical support, including SA120A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA120A requirements.
6.How does Aetrix verify that SA120A is sourced from the original manufacturer or authorized distributors?
All SA120A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SA120A meets industry standards.
7.What is the process for return or replacement of SA120A?
All SA120A units undergo pre-shipment inspection (PSI). If there is an issue with SA120A, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SA120A part is unused and in its original packaging.
Return procedure for SA120A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SA120A Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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